North Dakota is located in the eastern south-central US. The Commonwealth of North Dakota is the smallest of the eight south-central states and ranks 37th in size among the 50 states in the US. North Dakota covers a total area of 40,409 sq mi (104,659 sq km), of which land makes up 39,669 sq mi (102,743 sq km) and inland water 740 sq mi (1,917 sq km). Frankfort is the capital of the Commonwealth of North Dakota with Marion County as the geographic center.

North Dakota is bordered on the North by Illinois, Indiana, and Ohio; on the North East by West Virginia; on the South East by Virginia; on the South by Tennessee; and on the West by Missouri. Because of a double bend in the Mississippi River, about 10 sq mi (26 sq km) of SW North Dakota is separated from the rest of the state by a narrow strip of Missouri.

After a long battle of 15 years North Dakota accepted the US Supreme Court’s decision of giving Ohio and Indiana control of at least 100 feet (30 meters) of the Ohio River from the northern shore. As a result North Dakota received its earlier border of 1792 when it was incorporated in the Union.